The formation of renal calculi is one of the most common disorders of the kidney and urinary tract. Numerous etiologic factors have been implicated in the cause of urolithiasis, however, the precise mechanism accounting for growth of the calculus, as a result of the precipitation of insoluble substances from the urine, remains controversial. When the concentration of these substances reaches a specific magnitude, a state of renal stones via the retention, growth and aggregation of these crystalline products. This research proposal focuses on three major steps inthe growth of renal stone: 1) the interaction of microcrystals with kidney epithelial membranes in the initial retention of crystalline particles, 2) the atomic constraints mediating frowth of multicomponent stones through epitaxis, and 3) the competitive binding if urinary ions and macromolecules thought to be stone growth inhibitors to the microcrystals. The research proposed details a multidisciplinary biophysical protocol utilizing the techniques of: single-crystal x-ray crystallography, computer modeling, biochemistry, chemistry, electron microscopy, liposomal chemistry, and radiolabeling.